The Mac Pro offers a similar casing to the Power Mac G5 that preceded it, but it replaces the older PowerPC processors with two dual-core Intel Xeon chips, as well as space for two optical disc drives and up to four hard drives. The standard $2,499 configuration includes 1GB of memory, an Nvidia GeForce 7300 GT graphics card, a 250GB hard drive and a SuperDrive that can burn CDs and DVDs.

"Today, the Power Mac is going to fade into history," said Jobs, wearing his trademark black mock turtleneck and blue jeans. At several points, Jobs handed off keynote duties to several lieutenants, including Senior Vice President Philip Schiller, who showed off the Mac Pro.

Apple didn't offer a full look at Leopard but instead showed off a top-10 list of new features the operating system is set to sport upon debuting next spring. Among the features Jobs showed off are a Time Machine option that automatically backs up a Mac. Other features include enhanced videoconferencing options, improved Mail and the inclusion of the Front Row media software and PhotoBooth picture-taking programs that previously have been available on only new Macs. (To see CNET Reviews' first take on the Leopard preview, click here.)

Video: A look at the Mac Pro Philip Schiller, Apple's senior vice president of worldwide product marketing, shows off the new Mac Pro based on Intel's Xeon 5100 processor.

To take advantage of Time Machine, users need a second hard drive. The software records a copy of every change made to a file, which required Apple to add extensions to Leopard's file system, Brian Croll, director of Mac OS X development, said in an interview following Jobs' keynote. Users can virtually "fly" back through time by scrolling through different windows that represent days, looking for the file they need while appearing to travel into a black hole.

Several improvements to the iChat text and multimedia conferencing software were also shown. Consumers will be able to add backdrops behind themselves, making it look like they were being interviewed for a cable news program. Those backdrops can also include video. Schiller drew perhaps the biggest laughs of the day as he pretended to ride a roller coaster while video conferencing off-stage with Jobs.

Familiar applications such as Mail, Dashboard and Spotlight will also be improved in Leopard, Jobs said. Mail users will be able to personalize e-mail messages with photos and create to-do lists from their e-mail. Custom widgets can be created with Web Clip, which can take information from any regularly updated Web page and display it as a widget in Dashboard. And Spotlight will now allow Mac users to search for files across their networks and on workgroup servers.

Jabs at Microsoft
Jobs led the attendees back through the major enhancements to the Mac OS X operating system, including the most recent version, Mac OS X 10.4, which is code-named Tiger. "This is what we've been doing for the past five years. What has our competitor been doing for the past five years?" he asked in one of many jabs at Microsoft, which has been working to ready the , the first completely new version since Windows XP debuted in October 2001.

In addition to the Mac Pro, Apple also introduced its first Intel-based Xserve server, also sporting two dual-core Xeon chips. A sample configuration with two 2GHz Xeons, 1GB of memory and a single 80GB Serial ATA hard drive sells for $2,999.

Apple has added several nice features in Leopard, especially with the Time Machine backup software, said Bob O'Donnell, an analyst at IDC. But the fact that Apple won't ship the update until next spring is disappointing, in light of Microsoft's Vista delays, he said.

"They had a huge, gaping window of opportunity if they could ship this fall," O'Donnell said. Apple did ship a major update to Mac OS X this year, with porting of Tiger to Intel's processors, and maybe it wasn't realistic to get Leopard out any sooner. But now there's "a good chance" that Leopard won't ship until after Vista, he said.

Apple had previously said it would ship Leopard by the end of this year or the beginning of next. Microsoft has said it will deliver the consumer version of Vista in January, but many industry analysts would not be surprised by another delay.

Apple also didn't mention anything about new hardware with Intel's Core 2 Duo chips, which were unveiled a few weeks ago. Some PC companies have already started shipping systems based on the Core Extreme processor and have talked about their plans for notebooks using Merom, the notebook version of the Core 2 Duo. Merom systems aren't expected to become available until later this month.